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LT3757/LT3757A - Boost, Flyback, SEPIC and Inverting Controller

The LT®3757/LT3757A are wide input range, current mode, DC/DC controllers which are capable of generating either positive or negative output voltages. They can be configured as either a boost, flyback, SEPIC or inverting converter. The LT3757/LT3757A drive a low side external N-channel power MOSFET from an internal regulated 7.2V supply. The fixed frequency, current-mode architecture results in stable operation over a wide range of supply and output voltages.

The operating frequency of LT3757/LT3757A can be set with an external resistor over a 100kHz to 1MHz range, and can be synchronized to an external clock using the SYNC pin. A low minimum operating supply voltage of 2.9V, and a low shutdown quiescent current of less than 1μA, make the LT3757/LT3757A ideally suited for batteryoperated systems.

The LT3757/LT3757A feature soft-start and frequency foldback functions to limit inductor current during start-up and output short-circuit. The LT3757A has improved load transient performance compared to the LT3757.

Features Wide Input Voltage Range: 2.9V to 40V Positive or Negative Output Voltage Programming with a Single Feedback Pin Current Mode Control Provides Excellent Transient Response Programmable Operating Frequency (100kHz to 1MHz) with One External Resistor Synchronizable to an External Clock Low Shutdown Current < 1μA Internal 7.2V Low Dropout Voltage Regulator Programmable Input Undervoltage Lockout with Hysteresis Programmable Soft-Start Small 10-Lead DFN (3mm × 3mm) and Thermally Enhanced 10-Pin MSOP Packages Typical Application

Applications Automotive and Industrial Boost, Flyback, SEPIC and Inverting Converters Telecom Power Supplies Portable Electronic Equipment Packaging

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